The present invention relates to video recording a plurality of signals, and more particularly where the recording channels have unequal bandwidths.
One method of recording video signals is the so called helical scan configuration in which the tape describes at least a portion of a helix about a drum within which are rotating recording heads. The heads rotate at a rate determined by the frame rate of the television standard of the video signal being recorded. One possibility for recording NTSC signals is to have the two chroma signals (I and Q) frequency modulate carriers having frequencies of 5 MHz and 1.5 MHz respectively. These carrier frequencies are high enough to allow for sufficient deviation to provide the required channel signal to noise ratios and bandwidths of 1.5 MHz and 0.5 MHz for the I and Q signals respectively. If the signals to be recorded conform to the PAL or SECAM standards, then the frame rate, and therefore the head rotation rate, is normally lower than for the NTSC standard, which reduces the recording channel bandwidth. Further the chroma signals to be recorded (U and V for PAL, R-Y and B-Y for SECAM) require a 1.5 MHz channel bandwidth for both signals. This bandwidth requires carrier frequencies that are not realizable with at least one form of recorder, such as the "Hawkeye" manufactured by RCA Corporation, since it is beyond the frequency response limit. It is possible to use the above described NTSC recording system with 5 MHz and 0.5 MHz carriers for
or SECAM signals by restricting the bandwidth of one of the chroma signals, but this would result in an unacceptable picture. If both chroma signals were equally affected, the picture would be more acceptable.
It is therefore desirable to use unequal bandwidth transmission channels with a plurality of signals so that the signals are equally affected.